/**
 * KopsoxFramework
 * Copyright (C) 2010 Free Software Foundation, Inc. <http://fsf.org/>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.kopsox.validation.impl.value;

import java.io.Serializable;

import org.kopsox.comm.message.ValueMessage;
import org.kopsox.comm.message.impl.ErrorMessageImpl;
import org.kopsox.data.Value;
import org.kopsox.general.priority.PriorityEnum;
import org.kopsox.general.type.ErrorTypeEnum;
import org.kopsox.validation.Validator;
import org.kopsox.validation.impl.AbstractValidator;

/**
 * Checks if the new value is the same as the old value<br>
 * If not, the Validation fails
 * 
 * @author Konrad Renner - 08.09.2010
 *
 */
public final class ReadonlyValidator extends AbstractValidator {
	private static final long serialVersionUID = -4592993197567925959L;
	private final static String name = "ReadonlyValidator";
	
	public ReadonlyValidator() {
		setPriority(PriorityEnum.HIGHEST.getPriority());
	}

	/* (non-Javadoc)
	 * @see org.kopsox.validation.Validator#validateValueMessage(org.kopsox.comm.message.ValueMessage)
	 */
	@Override
	public boolean validateValueMessage(ValueMessage value) {
		super.errorMessages.clear();
		boolean ok = true;
		
		Value<Serializable> v = value.getMessageValue();
		
		if((v == null || v.getValue() == null) && value.getOldValue() != null) {
			ok = false;
			ErrorMessageImpl message = new ErrorMessageImpl(PriorityEnum.HIGHEST.getPriority(), ErrorTypeEnum.READONLY);
			message.setNameOfErrorSource(v==null?null:v.getValueDescriptor().getName());
			message.setMessageSender(this);
			super.errorMessages.add(message);
		}else if(v != null && v.getValue() != null && !v.getValue().equals(value.getOldValue())) {
			ok = false;
			ErrorMessageImpl message = new ErrorMessageImpl(PriorityEnum.HIGHEST.getPriority(), ErrorTypeEnum.READONLY);
			message.setMessageSender(this);
			message.setNameOfErrorSource(v.getValueDescriptor().getName());
			super.errorMessages.add(message);
		}
		
		return ok;
	}

	public String toString() {
		return name;
	}
	
	/**
	 * Returns true if the Validator is a 'Show-Stopping'-Validator.<br>
	 * A 'Show-Stopping'-Validator is an Validators which stops the validation process, if he fails.<br>
	 * This means, that after this Validator no other Validator is called, if the method 'validateValueMessage' returns false!<br>
	 * <b>NOTE:</b>This Validator is a 'Show-Stopping'-Validator
	 * 
	 * @return boolean
	 */
	@Override
	public boolean isShowStoppingValidator() {
		return true;
	}

	/**
	 * The Readonly-Validator must be called with the highest priority.<br>
	 * So this compareTo-Method returns always -1, except the other Validator is also an Readonly-Validator<br>
	 * 
	 * @param o - Validator
	 */
	@Override
	public int compareTo(Validator o) {
		if(o instanceof ReadonlyValidator) {
			return 0;
		}
		
		return -1;
	}
}
